Well, just like in your other topic about starting a new Facebook group for Inkscape, I suspect there probably already is a Facebook group for Scribus. I can't search for it, since I don't have a FB account. But probably is there somewhere.

Unfortunately, not. It's been very frustrating since I like quite a lot of FOSS and there are no "centralized" modes to interact with other people (not each of them available at the same time on Twitter/Facebook/Google groups at once).So I decided to give this a twist, I created groups about software and topics I prefer, I don't expect everyone likes the same set of software/technologies but I would like to attract passionates in each category under one "flag".

Well, I broadened the audience target renaming the group from "Scribus unofficial" to "simple desktop publishing (dtp)", because I also want to discuss other softwares (like Publisher).Anyhow, the URL is still the same and everyone's welcome.

This forum is pretty much the central place for user support for Inkscape (well, except for your new, and other existing social media outlets). Inkscape also has a user community mailing list and and IRC channel, where you can get support. (and another much smaller English forum, and several forums in other languages)

Although the mailing list and IRC aren't really meant for "social encounters" other than Inkscape support. This forum doesn't tend to be all that social either, really. I've never been sure why.

Some of us have tried to have drawing challenges and/or contests, from time to time, both here (in Competitions board) or over on the forum in my signature. But it never lasts very long.

My best assessment is that what functionality Inkscape provides serves a really, really wide range of professions and hobbies. For hobbies, people do those in their spare time, and not all day long. But most of them probably have to work all day. For professions like artists or graphic artists, maybe they're just using Inkscape all day at work, and don't want to play with it at home? For other professions, like math, rocket scientists, teachers, doctors, and many, many more, they really only need Inkscape for very specific, and usually short projects, and don't want to play with it otherwise.